My invention pertains to manual block traffic control and signaling systems for railroads. More particularly, the invention relates to a traffic control and signaling system, for a single track railroad, which is manually controlled by operators at adjacent stations and which does not provide continuous track circuit train detection between such stations.
There are many stretches of railroad throughout the world on which the volume of traffic does not warrant an extensive and sophisticated centralized traffic control and signaling system. In many situations or locations, the local economy and resources and the economics of the existing traffic level do not even warrant nor permit the installation of a less sophisticated signaling system such as automatic permissive block with full train detection and automatic opposing traffic protection. Yet in all places safety concerns make some form of simple traffic supervision with train movement control signals desirable, in order to protect lives and property where train operation, particularly in opposing directions on a single track, is otherwise without signals. On such low traffic railroads, a control system which requires the least initial apparatus and installation expense can find use and is desirable. Such systems may use manual control and participation by station operators who are already employed and have other duties. These operators will be located at siding locations where trains may meet or pass and may thus govern the movement of the trains to and from adjacent stations along the single track railroad. A form of check-in and check-out train detection, to avoid the installation of continuous track circuits for train detection, may be made a part of the system. Such apparatus preferably is of a modular arrangement for easy maintainence and simple upgrading, as increased traffic warrants improvements. In other words, a manually controlled station-to-station block signaling arrangement of traffic control which provides protection against opposing train movements in single track and has low cost is a highly desirable improvement for light traffic railroads.
Accordingly, an object of my invention is a traffic control system for single track railroads.
Another object of the invention is a traffic control system for single track railroads without continuous train detection between stations and with station-to-station control blocks and an operator's console at each station for manual control of the intervening block.
Still another object of the invention is a manual block signaling system for railroads, with train detection only at interlocking station locations, which requires positive action by operators at adjacent stations to authorize train movement from the requesting station to the far station at the other end of the single track block and which further requires the operator at the far station to manually confirm the completed arrival of the train before the traffic locking for that train can be released.
A further object of my invention is a traffic control and signaling system, for single track railroads without track circuits between stations, in which authorization for train movement from a first to a second station at the ends of a single track stretch is initiated by the operator at the departure station, acknowledged and completed by the operator at the other station, and which protects that train from opposing train movements during passage through the single track stretch.
Another object of my invention is a manual block traffic control and signal system for a single track railroad without continuous train detection in the single track stretches between adjacent stations, in which a request for a train movement is manually initiated by the operator at the departure or near station, transmitted as a first signal, having a predetermined characteristic, over a communication channel between the stations, and registered at the far end station; acknowledgement of the received request by the far station operator initiates the transmission of a distinct characteristic second signal over the channel to the near station where reception establishes the requested traffic direction and clears the departure signal for the train; acceptance of the signal and movement of the train into and through the single track locks the communication channel and thus the system to inhibit any action by the operators to change traffic direction or clear a signal for any opposing or following moves, the far operator confirms the detected arrival of the train to initiate the reset of the far station apparatus and the transmission of a third signal over the channel to the near station where its reception actuates the reset of the entire system including the communication channel to enable the preparation for the subsequent movement of a train in either direction.
Yet a further object of my invention is a manual block traffic control system for a stretch of single track railroad without track circuits and with operators at each of adjacent stations, in which a manually initiated request for train movement is transmitted over a first polarized line circuit from the leaving station to the arrival station, a manually initiated acknowledgement is transmitted back over a second polarized line circuit from the far to the near station to establish traffic direction and authorize train movement, the line circuits are locked out during such train movement, and the arrival of the complete train at the far station is manually confirmed to initiate restoration of the line circuits to clear out the traffic locking and release the single track block for further train movements.
A still further object of the invention is a manual block traffic control and signal system for a single track railroad without continuous train detection between two adjacent stations at either end of a single track stretch, in which a manually initiated first signal of selected polarity requesting a train movement from the originating one station to the other station is transmitted over a normally deenergized two-wire line circuit between the two stations and registered at the other station, a second signal of opposite polarity is manually initiated and transmitted from the other station to acknowledge and accept the train movement request, reception of the second signal at the one station establishing traffic direction and clearing the departure signal, movement of the train into the single track deenergizing the line circuit and locking the traffic direction to protect the train, and transmission of a manually initiated third signal confirming train arrival at the other station releases system traffic locking and deenergizes the line circuit to reset the system for subsequent train moves.
Other objects, features, and advantages of my invention will become apparent from the following description and appended claims when taken in connection with the accompanying drawings.